The repair and replacement of diseased tissue structures and organs requires an enormous expenditure of health-care resources. For example, approximately 500,000 coronary artery bypass surgeries are performed each year in the United States. The most common treatment, replacement with an autograft, produces less than optimal results—a graft patency of approximately 50-70% at 10 years with accelerated graft closure over time (Nerem et al. (1997) Tissue Engineering and the Vascular System: Synthetic Biodegradable Polymer Scaffolds (eds. Atala & Mooney) Boston, Birkhauser, pp. 165-85). While there are numerous prosthetic products in use, these also have limited lifetimes and elicit many unfavorable reactions in the body.
Accordingly, there is a need for bioengineered tissue substitutes, such as blood vessel substitutes and muscle substitutes, that can be custom-engineered to match the biomechanical, biochemical, and biological needs of the specific tissue or organ they are designed to replace.